[PATCH v3 04/22] xen/arm: Introduce CONFIG_DEVICE_TREE_NUMA config option

[Hirokazu Takahashi <taka@xxxxxxxxxxxxx>]

Introduce the CONFIG_DEVICE_TREE_NUMA configuration option for
Device Tree-based NUMA support. Selecting CONFIG_ARM_NUMA enables
CONFIG_DEVICE_TREE_NUMA, which in turn automatically selects CONFIG_NUMA.
While this option is currently restricted to the ARM architecture, it
is designed to be selectable for RISC-V and PPC in the future.

This patch also includes the necessary compilation fixes required when
building with CONFIG_NUMA, and creates a single fake NUMA node to ensure
Xen can boot successfully at this stage.

Signed-off-by: Hirokazu Takahashi <taka@xxxxxxxxxxxxx>
---
 xen/arch/arm/Kconfig   | 8 ++++++++
 xen/arch/arm/setup.c   | 4 ++++
 xen/arch/arm/smpboot.c | 2 ++
 xen/common/Kconfig     | 8 ++++++++
 4 files changed, 22 insertions(+)

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 5fa89fcb24..c0c03cbd47 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -99,6 +99,14 @@ config MPU
          systems supporting EL2. (UNSUPPORTED)
 endchoice
 
+config ARM_NUMA
+       bool "Device tree based NUMA support (UNSUPPORTED)" if UNSUPPORTED
+       select DEVICE_TREE_NUMA
+       help
+         Device tree based NUMA support. The "numa-node-id" property in
+         the CPU and memory nodes of a Device Tree defines the NUMA node
+         to which they belong.
+
 source "arch/Kconfig"
 
 config ACPI
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 6310a47d68..c0202d9ff6 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -351,6 +351,10 @@ void asmlinkage __init noreturn start_xen(unsigned long 
fdt_paddr)
     /* Parse the ACPI tables for possible boot-time configuration */
     acpi_boot_table_init();
 
+#ifdef CONFIG_NUMA
+    numa_initmem_init(0x0UL, 0x1UL << (PADDR_BITS - 12));
+#endif /* CONFIG_NUMA */
+
     end_boot_allocator();
 
     /*
diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index 7f3cfa812e..d1651fe7dd 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -47,8 +47,10 @@ integer_param("maxcpus", max_cpus);
 /* CPU logical map: map xen cpuid to an MPIDR */
 register_t __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
 
+#ifndef CONFIG_NUMA
 /* Fake one node for now. See also xen/numa.h */
 nodemask_t __read_mostly node_online_map = { { [0] = 1UL } };
+#endif /* CONFIG_NUMA */
 
 /* Xen stack for bringing up the first CPU. */
 static unsigned char __initdata cpu0_boot_stack[STACK_SIZE]
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index 5ff71480ee..bfb3a3c007 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -188,6 +188,14 @@ config VM_EVENT
 config NEEDS_LIBELF
        bool
 
+config NUMA_DISTANCE_MAP
+       bool
+
+config DEVICE_TREE_NUMA
+       bool
+       select NUMA
+       select NUMA_DISTANCE_MAP
+
 config NUMA
        bool
 
-- 
2.43.0